In general, a sliding door device is applied to a large commercial vehicle such as a bus so that a large number of occupants may easily get on and off.
The sliding door device includes a sliding door installed to move along a guide rail provided in a vehicle body to open and close a door opening formed in the vehicle body, a pneumatic cylinder as a power source for moving the sliding door, a micro switch for sensing the closing of the sliding door, and a controller for controlling the pneumatic cylinder based on a sensing signal of the micro switch to control the opening and closing of the sliding door.
In addition, the sliding door device realizes a sliding door safely closing function for preventing an object from being damaged or an occupant from being injured when the object or the occupant is jammed in a space between the sliding door and the door opening in a process of closing the sliding door where the sliding door blocks the door opening.
That is, in the sliding door safely closing function, when the object or the occupant is jammed in the space between the sliding door and the door opening in the process of closing the sliding door, the sliding door is moved in a reverse direction, that is, in a direction where the door opening is opened so that it is possible to prevent the object or the occupant from being jammed.
In a method of sensing that the object or the occupant is jammed, a change in internal pressure of a weather strip attached to the sliding door to release shock and to maintain air-tightness is used. That is, when the object or the occupant is jammed, pressure is applied to the weather strip so that a change in pressure is generated. The change in the internal pressure of the weather strip is sensed to determine whether the object or the occupant is jammed.
According to the above-described conventional sliding door device, in order to prevent a malfunction from being caused by compression of the weather strip when the sliding door is closed, in a predetermined range immediately before the sliding door is completely closed, for example, in a range of 30 mm immediately before the sliding door is completely closed, although an object, such as clothes, or a shoulder strap of an occupant, or a part of the occupant's body, is jammed in the sliding door, the device ignores the jammed object or occupant is jammed and the sliding door continues closing so that the object may be damaged or the occupant may be injured.
On an incline, the sliding door may be closed by self-loading before the micro switch senses the closing of the sliding door so that an erroneous sensing may be generated in which the micro switch may not correctly sense the closing of the sliding door. In order to prevent erroneous sensing from being generated, a point in time when the closing of the sliding door is recognized by the micro switch is set to be earlier than a point in time when the closing of the sliding door is completed at a predetermined interval, for example, 30 mm.
Therefore, in a range of 30 mm immediately before the sliding door is completely closed, although the object, such as the clothes or the shoulder strap of the occupant or a part of the occupant's body, is jammed in the sliding door, the jammed object or occupant is ignored and the closing of the sliding door continues so that the object may be damaged or the occupant may be injured.
In addition, in a method of sensing that the object or the occupant is jammed, because the internal pressure of the weather strip is changed in accordance with a change in peripheral temperature of the weather strip so that a malfunction may be caused, it is determined that the object or the occupant is jammed only when pressure of no less than a predetermined pressure, for example, pressure of no less than 4.5±0.5 kgf is sensed in the weather strip.
Therefore, when an object or a part of an occupant's body of no more than, for example, 30×60 mm is jammed, it is not sensed that the object or the occupant is jammed and the closing of the sliding door continues so that the object may be damaged or the occupant may be injured and the vehicle can be driven in a state where the occupant is jammed in the sliding door so that a casualty may occur.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.